U.S. patent application number 10/547003 was filed with the patent office on 2009-03-26 for dielectric sheet.
Invention is credited to Miki Hasegawa.
Application Number | 20090078449 10/547003 |
Document ID | / |
Family ID | 32923474 |
Filed Date | 2009-03-26 |
United States Patent
Application |
20090078449 |
Kind Code |
A1 |
Hasegawa; Miki |
March 26, 2009 |
Dielectric sheet
Abstract
To provide a dielectric sheet that can be used as an elastomer
connector in order to connect highly integrated circuit board and
fine pitch electronic parts. The dielectric sheet (10f) comprises a
first penetrating region (222c) having high permittivity, and a
second penetrating region (33a) having conductivity, the regions
are arranged and formed in such a way that they are alternatively
interspersed in longitudinal and crosswise directions in a
non-conductive sheet-shaped elastomer. The transverse thickness W2
and longitudinal thickness W5 in the first penetrating region
(222c) may be arbitrarily determined. Similarly, the transverse
thickness W3 and longitudinal thickness W5 in the second
penetrating region (33a) may be arbitrarily determined. The
dielectric sheet (10f) serves to compliment the circuit of
electronic parts (for example, the printing board) to be connected
thereto.
Inventors: |
Hasegawa; Miki; (Aichi,
JP) |
Correspondence
Address: |
RADER FISHMAN & GRAUER PLLC
LION BUILDING, 1233 20TH STREET N.W., SUITE 501
WASHINGTON
DC
20036
US
|
Family ID: |
32923474 |
Appl. No.: |
10/547003 |
Filed: |
February 27, 2004 |
PCT Filed: |
February 27, 2004 |
PCT NO: |
PCT/JP04/02591 |
371 Date: |
February 8, 2006 |
Current U.S.
Class: |
174/145 ;
174/137R |
Current CPC
Class: |
H05K 2201/0133 20130101;
H05K 2201/0187 20130101; H05K 1/162 20130101; H01L 21/486 20130101;
H01L 2924/0002 20130101; H05K 2203/0235 20130101; H05K 3/325
20130101; H05K 2201/0209 20130101; H05K 1/023 20130101; H01L
2924/0002 20130101; H01L 23/49827 20130101; H05K 2201/10378
20130101; H05K 2201/0314 20130101; H01L 2924/00 20130101 |
Class at
Publication: |
174/145 ;
174/137.R |
International
Class: |
H01B 17/00 20060101
H01B017/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 28, 2003 |
JP |
2003-054778 |
Claims
1. A dielectric sheet comprising: at least one first penetrating
region having high permittivity, the first penetrating region being
formed in a non-conductive sheet-shaped elastomer.
2. The dielectric sheet according to claim 1, wherein said at least
one first penetrating region having high permittivity is
interspersed on the non-conductive sheet-shaped elastomer.
3. The dielectric sheet according to claim 1, wherein said at least
one first penetrating region having high permittivity is arranged
with regularity in the non-conductive sheet-shaped elastomer.
4. The dielectric sheet according to claim 1, further comprising:
at least one second penetrating region having conductivity being
formed in the non-conductive sheet-shaped elastomer.
5. The dielectric sheet according to claim 4, wherein a same number
of said at least one first penetrating region having high
permittivity and said at least one second penetrating region having
conductivity are formed in the non-conductive sheet-shaped
elastomer.
6. The dielectric sheet according to claim 4, wherein said at least
one first penetrating region having high permittivity and said at
least one second penetrating region having conductivity are formed
in pairs.
7. The dielectric sheet according to claim 4, wherein said at least
one second penetrating region having conductivity intersperses in
the non-conductive sheet-shaped elastomer.
8. The dielectric sheet according to claim 1, said at least one
first penetrating region having high permittivity includes
ferroelectrics.
9. A pair of electronic parts characterized in that the pair of
electronic parts are connected with each other by the dielectric
sheet according to claim 1.
10. The dielectric sheet according to claim 2, wherein said at
least one first penetrating region having high permittivity is
arranged with regularity in the non-conductive sheet-shaped
elastomer.
11. The dielectric sheet according to claim 2, further comprising:
at least one second penetrating region having conductivity being
formed in the non-conductive sheet-shaped elastomer.
12. The dielectric sheet according to claim 3, further comprising:
at least one second penetrating region having conductivity being
formed in the non-conductive sheet-shaped elastomer.
13. The dielectric sheet according to claim 11, wherein a same
number of said at least one first penetrating region having high
permittivity and said at least one second penetrating region having
conductivity are formed in the non-conductive sheet-shaped
elastomer.
14. The dielectric sheet according to claim 12, wherein a same
number of said at least one first penetrating region having high
permittivity and said at least one second penetrating region having
conductivity are formed in the non-conductive sheet-shaped
elastomer.
15. The dielectric sheet according to claim 5, wherein said at
least one first penetrating region having high permittivity and
said at least one second penetrating region having conductivity are
formed in pairs.
16. The dielectric sheet according to claim 11, wherein said at
least one first penetrating region having high permittivity and
said at least one second penetrating region having conductivity are
formed in pairs.
17. The dielectric sheet according to claim 5, wherein said at
least one second penetrating region having conductivity
intersperses in the non-conductive sheet-shaped elastomer.
18. The dielectric sheet according to claim 6, wherein said at
least one second penetrating region having conductivity
intersperses in the non-conductive sheet-shaped elastomer.
19. The dielectric sheet according to claim 2, said at least one
first penetrating region having high permittivity includes
ferroelectrics.
20. The dielectric sheet according to claim 3, said at least one
first penetrating region having high permittivity includes
ferroelectrics.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a dielectric sheet disposed
between circuit boards such as printed circuit boards and various
circuit components.
RELATED ART
[0002] In recent years, more and more electronic devices have
reduced their sizes and thickness and it has become dramatically
desirable to implement a connection between small circuits or a
connection between a small component and a small circuit. As
examples of such connections, there may be solder joining or
joining with anisotropic conductive adhesives. In another example,
an anisotropic conductive elastomer sheet may be disposed between
an electronic component and a circuit board for conduction of
electricity therebetween.
[0003] The anisotropic conductive elastomer sheet herein is
referred to as an elastomer sheet that has conductivity in a
certain direction only. Some anisotropic conductive elastomer
sheets exhibit conductivity only in a direction of thickness, and
others exhibit conductivity in the direction of thickness only when
pressed in the direction of thickness.
[0004] The anisotropic conductive elastomer sheets can achieve an
electronic connection in a simple way without using soldering,
mechanical fitting, or the like and also can achieve the connection
to absorb mechanical impact and strain. Therefore, anisotropic
conductive elastomer sheets are widely used in such fields as a
liquid crystal display, a cellular phone, an electronic computer,
an electronic digital clock, an electronic camera, a computer and
the like.
[0005] The anisotropic conductive lastomer sheets are also widely
used as electronic connectors for connecting a circuit apparatus
such as a printed circuit board, and a leaderless chip carrier or a
liquid crystal panel. An elastomer connector is a connector
utilizing elastomer such as conductive rubber disposed between
electrodes to obtain an electrical connection simply by pressing
the electrodes. One of such types of elastomer connectors may
include an anisotropic conductive elastomer sheet having properties
of being insulative in a horizontal direction and conductive in a
vertical direction.
[0006] In the testing of electrical connections of circuit
apparatus such as printed circuit boards and semiconductor
integrated circuits, a sheet of anisotropic conductive elastomer is
interposed and makes an electrical connection between an electrode
region to be tested which is formed on at least one surface of the
circuit apparatus to be tested and an electrode region of the
testing circuit board which is formed on at least one surface of
the testing circuit board.
[0007] Conventionally, it is known that an anisotropic conductive
block is firstly formed by integrating aligned metal wires by using
insulator and the resultant block is then sliced in a direction
perpendicular to the direction of the metal wire so as to make an
anisotropic conductive elastomer sheet. (As an example, referring
to Japanese Laid-Open Patent Publication No. 2000-340037)
[0008] The use of metal wire in the anisotropic conductive
elastomer sheet, however, makes it difficult to shorten the
distance between the wires, therefore it is not easy to surely
obtain the fine pitch that is demanded for anisotropic conductivity
in the highly integrated circuit boards and electrical components
in recent years. Metal wires are susceptible to a compressive
buckling and may be dropped off from the sheet when used repeatedly
such that the anisotropic sheet may not fully conduct performance
thereof.
[0009] Elastomer connectors, employed recently in the highly
integrated high-density circuit board and in the fine pitch
electrical components for the electrical connections, can secure an
assembling space when the electrical elements are incorporated in
the elastomer connectors.
[0010] The incorporation of the electrical element into the
elastomer connectors for the testing of the electrical connections
of the circuit apparatus such as printed circuit boards and
semiconductor integrated circuits can improve the accuracy of
measurement.
SUMMARY OF THE INVENTION
[0011] In view of the above, the present invention it is an object
to provide a dielectric sheet used as an elastomer connector of
today's highly integrated circuit board and fine pitch electrical
components.
[0012] In order to satisfy the above objectives, inventors of the
present invention invented a novel dielectric sheet below.
[0013] (1) A dielectric sheet comprising: at least one first
penetrating region having high permittivity, the first penetrating
region being formed in a non-conductive sheet-shaped elastomer.
[0014] (2) The dielectric sheet according to (1), wherein said at
least one first penetrating region having high permittivity is
interspersed on the non-conductive sheet-shaped elastomer.
[0015] (3) The dielectric sheet according to (1) or (2), wherein
said at least one first penetrating region having high permittivity
is arranged with regularity in the non-conductive sheet-shaped
elastomer.
[0016] (4) The dielectric sheet according to any one of (1) to (3),
further comprising: at least one second penetrating region having
conductivity being formed in the non-conductive sheet-shaped
elastomer.
[0017] (5) The dielectric sheet according to (4), wherein a same
number of said at least one first penetrating region having high
permittivity and said at least one second penetrating region having
conductivity are formed in the non-conductive sheet-shaped
elastomer.
[0018] (6) The dielectric sheet according to (4) or (5), wherein
said at least one first penetrating region having the high
permittivity and said at least one second penetrating region having
conductivity are formed in pairs.
[0019] (7) The dielectric sheet according to any one of (4) to (8),
wherein said at least one second penetrating region having
conductivity intersperses in the non-conductive sheet-shaped
elastomer.
[0020] (8) The dielectric sheet according to any one of (1) to (7),
said at least one first penetrating region having high permittivity
includes ferroelectrics.
[0021] (9) A pair of electronic parts comprising the pair of
electronic parts are connected with each other by the dielectric
sheet according to any one of (1) to (8).
[0022] The present invention may be characterized in that at least
one first penetrating region having high permittivity is formed in
a non-conductive sheet-shaped elastomer.
[0023] The "permittivity" referred herein may represent a relative
permittivity. The permittivity differs according to the physical
properties of the first penetrating region. In most cases, the
first penetrating region has a higher permittivity than a
sheet-shaped elastomer. The region having "high permittivity"
represents a state in which the region has a higher permittivity
than the adjacent region.
[0024] The first penetrating region having high permittivity may
thus be formed with materials having high permittivity. The
material that has high permittivity, for example, is
ferroelectrics.
[0025] An example of ferroelectrics includes barium titanate
(BaTiO3) that is an oxide of perovskite, lead titanate (PbTiO3),
lithium niobate (LiNbO3) and lithium tantalite (LiTaO3). The first
penetrating region may include any materials of above
ferroelectrics in a shape of piece, particle, flake, or powder.
[0026] A "penetrating region" is formed to have predetermined areas
on both front surface and back surface of the sheet-shaped
elastomerand a thickness, that is, the region penetrates from the
front surface to the back surface of the sheet-shaped elastomer),
and may be considered that the region has a volume as an object.
The penetrating region appearing on front or back surface of the
sheet-shaped elastomer may be of circular or of any other
shape.
[0027] The first penetrating region having high permittivity is
formed of materials including high dielectric particles. The high
dielectric particles in the first penetrating region may be
distributed evenly or unevenly. Additionally, the high dielectric
particle may be included in a region other than the first
penetrating region. The number of high dielectric particles
included in a dielectric sheet may change dramatically in a
boundary between the first penetrating region and the sheet-shaped
elastomer, or may decrease gradually from the first penetrating
region toward a region that is formed of sheet-shaped
elastomer.
[0028] The boundary in the first penetrating region may be, but not
necessarily formed in a way that the region is able to be observed
as required. In addition, the boundary in the first penetrating
region may be specified by average content of high dielectric
particle within a predetermined range from the center of the
penetrating region.
[0029] In the case where the first penetrating region is of
circular shape, the boundary is determined in a way mentioned
below. The first penetrating region is sandwiched by aforementioned
circular electrode such that the center of the circular electrode
having a predetermined diameter is aligned with the first
penetrating region, and then the capacitance in the first
penetrating region is measured as a solid capacitor. The
capacitance increases as the diameter of the circular electrode is
made larger until it reaches to a point where the capacitance does
not go beyond a fixed value even if the diameter of the circular
electrode is still made larger. The diameter of the circular
electrode with the capacitance remaining constant may thus be
determined as a boundary of the first penetrating region.
Alternatively, a specified value is firstly determined while the
capacitance is still on the increase, and the boundary of the first
penetrating region may be determined when the diameter of the
circular electrode equals to the predetermined value. In the case
where the first penetrating region is of rectangular shape, the
boundary is determined in a similar way as above.
[0030] The term "non-conductive" herein refers to as a state
wherein the conductivity is sufficiently low or the electric
resistance is sufficiently high. On the other hand, for a
sheet-shaped elastomer, as a whole, the term "non-conductive"
should mean that the sheet have a non-conductivity that can provide
sufficient non-conductivity in a non-conductive direction of a
sheet that is of such arrangement. The electric resistance in this
case is preferably no less than 10 kilo-ohms (k.OMEGA.), more
preferably no less than 100 kilo-ohms (k.OMEGA.), and further
preferably no less than 1 milliohm (m.OMEGA.).
[0031] The term "sheet-shaped" herein refers to as a flat plate of
a generally considerable sheet shape. The plate may be of a
circular or a rectangular shape. The thickness of the sheet-shaped
elastomer plate, however, should be thin and even as possible.
[0032] Non-conductive sheet-shaped elastomer may be an elastomer
sheet formed with elastomer materials having no conductivity in a
shape of sheet.
[0033] Specifically, elastomer materials having no conductivity
include: a cross-linked natural rubber, a polyisoprene rubber, and
butadiene copolymer such as butadiene-styrene,
butadiene-acrylonitrile, and butadiene-isobutylene, and conjugate
diene rubber, and hydrogenated material thereof. Other than above,
used as elastomer materials having no conductivity further include:
block copolymer rubber such as styrene-butadiene-diene block
copolymer rubber and styrene-isoprene block copolymer, and
hydrogenated thereof. And chlorobutadiene polymer,
chloroethene-polyvinyl copolymer, urethane rubber, polyester
rubber, epichlorohydrin rubber, ethene-propylene copolymer rubber,
ethene-propylene-diene copolymer rubber, flexible liquid epoxy
rubber, silicone rubber or fluorine rubber are also used.
[0034] Among these material, silicone rubber, which is superior in
heat-resistance, cold-resistance, chemical-resistance,
weather-resistance, electrical isolation and safety, is preferably
used.
[0035] Members formed of conductive elastomer or non-conductive
elastomer may be coupled with a coupling agent to compose a
dielectric sheet. A coupling agent coupling members formed of
conductive elastomer and non-conductive elastomer may not be
particularly limited to any bonding agent so long as bonding these
members and any commercially available adhesives may be used.
Specifically, coupling agent such as such as silane, aluminum, and
titanate, and silane coupling agent is preferably used.
[0036] In the dielectric sheet according to the present invention,
two electrodes are opposingly disposed adjacent to the first
penetrating region having a high permittivity, and voltage is given
between two electrodes for the dielectric sheet to serve as a solid
capacitor.
[0037] The shape of first penetrating region may be identical with
the opposing shape of the electrode, or may be different from the
opposing shape of the electrode. It is preferable, however, that
the first penetrating region is of an identical shape with the
opposing shape of the electrode. An appropriate determination of
size and thickness of the first penetrating region and the contents
of high dielectric particle therein (i.e., high permittivity) is
equal to a provision of a capacitor having a desired capacitance to
a sheet-shaped elastomer connector.
[0038] The aforementioned electrode should not be particularly
provided, but instead, may be replaced with land pattern on the
non-mounted surface (pattern surface) in printing boards. A
disposition of the first penetrating region between the land
patterns in the printing board is equal to a provision of a desired
capacitor to the elastomer connector.
[0039] In the present invention comprising the first penetrating
region having high permittivity intersperses in the non-conductive
sheet-shaped elastomer.
[0040] In the statement "the first penetrating region intersperses"
means that the first penetrating region is spread out over the
region, but does not necessarily mean that they are disposed
disarray. The first penetrating region may be formed either
disarray or with regularity in a sheet-shaped elastomer which is a
dielectric sheet body. The statement "intersperses disarray" means
that the region is dispersed to be distributed with no regularity,
however it means not only that the first penetrating region is
formed disarray without predetermined disposition, but also that
the first penetrating region is suitably arranged at a
predetermined disposition in a sheet-shaped elastomer with no
regularity.
[0041] As described above, the first penetrating region in this
invention serves as a capacitor and can determine a desired
capacitance according to the area and composition of the first
penetrating region. The dielectric sheet can be used, for example,
as an elastomer connector. A printing board is disposed between the
sheet-typed elastomer connectors to adjust the disposition of the
first penetrating region to the disposition of the land pattern of
the printing board, thereby complementing the circuit of the
printing board.
[0042] The present invention is characterized in that the first
penetrating region having high permittivity is arranged on the
non-conductive sheet-shaped elastomer with regularity.
[0043] The statement "arrangement with regularity" means a form of
appropriate disposition in which a penetrating region is formed in
a predetermined position. As a specific example of the arrangement
with regularity, the first penetrating region that is formed in a
circular or rectangular shape can be arranged in a grid pattern.
The grid-shape may be in a shape of rectangular or rhombic.
Alternatively, circular or rectangular shaped first penetrating
region may be arranged at regular intervals in a single row. The
first penetrating region may be arranged concentrically. Such
plurality of the first penetrating regions may either be serial
capacitors or parallel capacitors.
[0044] If the arrangement pitch in the first penetrating region is
to be adjusted to the land pattern arrangement of the printing
board, it can be considered that the first penetrating region may
be arranged at regular intervals of 1/10 inches or 2.54 mm.
[0045] Inner leads, outer leads, or pads on IC chips have narrow
arrangement pitch, or fine pitch. In order to adjust to such fine
pitch, the arrangement pitch of the first penetrating region is
preferably about 70 micro-meters or less.
[0046] The dielectric sheet according to the present invention
comprises at least one first penetrating region having high
permittivity and at least one second penetrating region having
conductivity, formed respectively in the non-conductive
sheet-shaped elastomer.
[0047] The term "Second penetrating region having conductivity"
described above means a region composed of elastomer having
conductivity, and a region penetrating from the front surface
through the back surface of the sheet-shaped elastomer that
composes dielectric sheet body. The member composing the second
penetrating region may be an elastomer having conductivity in
itself, an elastomer made to have conductivity by pressure welding,
or an anisotropic conductivity elastomer having conductivity only
in one direction. Elastomer having conductivity may generally be
obtained by mixing elastomer having no conductivity in order to
keep the volume specific resistance low (1 ohm cm (.OMEGA.cm) or
less, for example) with elastomer having conductivity.
[0048] As for elastomer materials having no conductivity, the
elastomer materials having no conductivity that composes of
sheet-shaped elastomer having conductivity can be employed. Among
these elastomer materials having no conductivity, silicone rubber,
which is superior in heat-resistance, cold-resistance,
chemical-resistance, weather-resistance, electrical isolation and
safety, is preferably used.
[0049] Conductive elastomer is composed of mixing conductive
materials such as pure metals, alloys, or non-metallic powder (also
available in forms of flakes, pieces, foils, etc.) with elastomer
materials having no conductivity. Pure metals may include gold,
silver, copper, nickel, tungsten, platinum, and palladium. Other
metals may include SUS, phosphor bronze, and beryllium copper.
Non-metallic powder may be carbon powders, which may include carbon
nanotube and fullerene.
[0050] Corresponding with the selection of the conductive material
or mixing ratio of the conductive material into elastomer, the
volume specific resistance of the second penetrating region having
conductivity can appropriately be determined.
[0051] The statement "at least one first penetrating region and at
least one second penetrating region being respectively formed" may
means, based upon the assumption that the first penetrating region
serves as a capacitor and the second penetrating region serves as a
signal line, that a smoothing circuit is composed of. Smoothing
circuit generally uses a signal line (also generally described as a
resistance having inner resistance) and a capacitor.
[0052] Smoothing circuits are widely used in electrical circuits
and electronic circuits as a use of rectifier circuits for
alternating current or shaping circuits for distorted wave.
[0053] As described above, the dielectric sheet according to the
present invention serves as a smoothing circuit, and can determine
a desired capacitance according to the area and composition of the
first penetrating region. Additionally, corresponding with the area
of second penetrating region, selection of the conductive material
or mixing ratio of the conductive material into elastomer, the
resistance can appropriately be determined.
[0054] The dielectric sheet disposes the printing board
therebetween, and the arrangement of the first penetrating region
and second penetrating region is adjusted to the land pattern
arrangement of the printing board, thereby complementing the
smoothing circuit to the printing board.
[0055] The dielectric sheet according to the present invention
comprising that a same number of first penetrating region having
high permittivity and second penetrating region having
conductivity, respectively, are formed therein.
[0056] In this case, it is only necessary that a same number of the
first penetrating region and second penetrating region are formed
on a dielectric sheet, irrespective of the form of their
arrangement. In other words, the first penetrating region and
second penetrating region may be arranged adjacent to or away from
each other. Alternatively, the first penetrating regions are
arranged adjacent to or away from each other, or similarly, the
second penetrating regions are arranged adjacent to or away from
each other.
[0057] In addition, individual value of electrical property of a
plurality of first penetrating regions or a plurality of second
penetrating regions may not necessarily be identical. According to
the object of complementing a smoothing circuit in the printing
board disposed between the dielectric sheets, a plurality of
smoothing circuits having different property values can be circuit
formed on the dielectric sheet.
[0058] The dielectric sheet according to the present invention
comprising that the first penetrating region having high
permittivity and the second penetrating region having conductivity
are formed in pairs in the non-conductive sheet-shaped
elastomer.
[0059] The statement "the first penetrating region and the second
penetrating region are formed in pairs" means that a number of
formation of the first penetrating region and a number of formation
of the second penetrating region are identical, and on top of that,
the first penetrating region and the second penetrating region are
formed in such a way that they are adjacent to each other in pairs,
and a plurality of smoothing circuits are formed in the
sheet-shaped elastomer.
[0060] A plurality of smoothing circuits having identical property
values may be formed in the sheet-shaped elastomer, or a plurality
of smoothing circuits having different property values may be
formed in the sheet-shaped elastomer, and their arrangement may be
appropriately determined.
[0061] The dielectric sheet according to the present invention
comprising that the first penetrating region having high
permittivity and the second penetrating region having conductivity,
respectively, are interspersed in the non-conductive sheet-shaped
elastomer.
[0062] The statement "the first penetrating region and the second
penetrating region, respectively, are interspersed" does not
necessarily mean that the first penetrating region and the second
penetrating region are interspersed with no regularity, but the
first penetrating region and the second penetrating region may also
be appropriately arranged with regularity in the sheet-shaped
elastomer.
[0063] Additionally, the first penetrating region and the second
penetrating region may be of an identical number or may be of
different number, as long as a plurality of the first penetrating
regions and the second penetrating regions are respectively formed
in the sheet-shaped elastomer.
[0064] Moreover, the first penetrating region and the second
penetrating region may or may not be formed in pairs. In other
words, the first penetrating region and the second penetrating
region may be arranged close with or may be arranged distanced with
each other in pairs. Alternatively, the first penetrating regions
are arranged adjacent to or away from each other, or similarly, the
second penetrating regions are arranged adjacent to or away from
each other.
[0065] In addition, individual value of electrical property of a
plurality of first penetrating regions or a plurality of second
penetrating regions may not necessarily be identical. According to
the object of complementing a smoothing circuit in the printing
board disposed between the dielectric sheets, a plurality of
electrical elements having different property values can be circuit
formed on the dielectric sheet. This can provide greater degree of
freedom of the circuit designing. For example, .pi.-circuit having
an increased number of stages of capacitor and resistance in the
smoothing circuit will also be available.
[0066] Further, in the present invention, the first penetrating
region having high permittivity may comprise ferroelectrics.
[0067] Typical materials as ferroelectrics include aforementioned
perovskite oxide. It may be preferable, however, that barium
titanate (BaTiO3), employed in solid capacitors for the purpose of
making use of its high permittivity, may be included in the
elastomer as ferroelectrics. It is also preferable that the outside
of the first penetrating region, that is, the sheet-shaped
elastomer, and the second penetrating region may not include barium
titanate (BaTiO3).
[0068] Applications of the present invention include the dielectric
sheet connected to pairs of electronic parts. "Pairs of electronic
parts" means electronic parts that are made in pairs. More
specifically, it means parts that sandwiches a dielectric sheet
therebetween. Such electronic parts include printing boards or fine
pitch electronic parts (for example, semiconductor integrated
circuit). The electronic parts to be made in pairs may be of
identical types or different types of electronic parts such as
printing boards and semiconductor integrated circuits.
BRIEF DESCRIPTION OF THE DRAWINGS
[0069] FIG. 1A is a drawing showing an appearance of a dielectric
sheet according to one embodiment of the present invention.
[0070] FIG. 1B is a drawing showing an appearance of a dielectric
sheet according to another embodiment of the present invention.
[0071] FIG. 2A is a drawing showing an appearance of a dielectric
sheet according to the present invention showing a modified example
of the second penetrating region having conductivity further formed
on the dielectric sheet shown in FIG. 1A.
[0072] FIG. 2B is a drawing showing an appearance of a dielectric
sheet according to the present invention showing a modified example
of the second penetrating region having conductivity further formed
on the dielectric sheet shown in FIG. 2A.
[0073] FIG. 3A is a drawing illustrating a manufacturing method of
a dielectric sheet forming a plurality of rectangular-shaped first
penetrating regions.
[0074] FIG. 3B is a drawing illustrating a manufacturing method of
a dielectric sheet forming a plurality of circular-shaped first
penetrating regions.
[0075] FIG. 4A is a drawing illustrating a manufacturing method of
a smoothing circuit sheet in which a plurality of
rectangular-shaped first penetrating regions and second penetrating
regions are formed respectively.
[0076] FIG. 4B is a drawing illustrating a manufacturing method of
a smoothing circuit sheet in which a plurality of circular-shaped
first penetrating regions and second penetrating regions are formed
respectively.
[0077] FIG. 5 shows a process for laminating dielectric sheet
members and non-conductive sheet members in relation to a method
for manufacturing a dielectric sheet according to the present
invention.
[0078] FIG. 6 shows a process for cutting the laminated block
prepared by lamination as illustrated in FIG. 5.
[0079] FIG. 7 illustrates a process for laminating a non-conductive
sheet member and a striped sheet member having been cut off in FIG.
6.
[0080] FIG. 8A is a plan view of a dielectric sheet obtained in the
processes shown in FIGS. 5 to 7.
[0081] FIG. 8B is a transverse cross-sectional view of the
dielectric sheet shown in FIG. 8A;
[0082] FIG. 9 illustrates a process for laminating dielectric sheet
members, non-conductive sheet members, and conductivity sheet
members in relation to a manufacturing method of a smoothing
circuit sheet according to the present invention.
[0083] FIG. 10 shows a process for cutting off the laminated block
prepared by lamination as illustrated in FIG. 9.
[0084] FIG. 11 illustrates a process for laminating a
non-conductive sheet member and the striped sheet member cut off as
shown in FIG. 10.
[0085] FIG. 12A is a plan view of a smoothing circuit sheet
obtained in the processes shown in FIGS. 9 to 11.
[0086] FIG. 12B is a transverse cross-sectional view of the
smoothing circuit sheet shown in FIG. 12A.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0087] Referring to drawings, a description shall now be provided
hereinafter in detail of an exemplary embodiment of the invention.
The exemplary embodiment is given only as a preferred example of
the invention, therefore, it should be noted that the present
invention shall not be limited to the embodiment described here.
Where several embodiments are shown hereinafter, where like
elements have been given like numerical designations, and
explanation thereof may be omitted or simplified.
[0088] FIG. 1A is an appearance diagram of a dielectric sheet 10
according to a first embodiment of the present invention. The
dielectric sheet 10 according to the embodiment of the present
invention is a rectangular-shaped sheet, comprising first
penetrating region 2a having high permittivity formed in a shape of
rectangular in a non-conductive sheet-shaped elastomer. The
sheet-shaped elastomer 1 is composed of a silicone rubber, for
example.
[0089] FIG. 1B is an appearance diagram of a dielectric sheet 20
according to a second embodiment of the present invention, wherein
a first penetrating region 2b having high permittivity is formed in
a circular shape in a sheet-shaped elastomer 21.
[0090] In the first and second embodiments, the first penetrating
region having circular and rectangular shapes, respectively are
shown, however, the first penetrating region may be in any other
shape as desired. It may be, for example, a polygonal or elliptical
shape, or any other closed and curved surface.
[0091] The first penetrating regions 2a and 2b comprises a
ferroelectric member containing ferroelectric material (barium
titanate, (BaTiO3), for example) particles in a non-conductive
elastomer material that comprises sheet-shaped elastomer 1 and 21.
Specifically, the first penetrating regions 2a and 2b use a
silicone rubber mixed with barium titanate particles.
[0092] As one example of a manufacturing method of the
afore-mentioned dielectric sheets 10 and 20, a mold cavity
corresponding to a shape of the first penetrating regions 2a or 2b
is stamped through a sheet-shaped elastomer 1 or 21, a member
formed as a ferroelectric member is then inserted into the obtained
cavity to form the first penetrating region 2a or 2b. The first
penetrating region 2a or 2b inserted respectively as a molding
member is bonded with sheet-shaped elastomer 1 or 21 respectively
by a coupling agent. The sheet-shaped elastomer 1 and the first
penetrating region 2a has an identical thickness, and the
sheet-shaped elastomer 20 and the first penetrating region 2b has
an identical thickness.
[0093] In the above embodiment, a silicone rubber manufactured by
Mitsubishi Plastics, Inc. or Shin-Etsu Polymer Co., Ltd is
employed, and a silane coupling agent manufactured by Shin-Etsu
Polymer Co., Ltd is employed as a coupling agent.
[0094] It may be understood that the dielectric sheets 10 and 20
corresponds to a sheet being characterized in that the conductive
material in the anisotropic conductive sheet type elastomer
connector is replaced with the ferroelectric first penetrating
regions 2a or 2b.
[0095] Whereas it is an object of the anisotropic conductive sheet
type elastomer connector to obtain electric conductivity between
the electronic parts, it is an object of the dielectric sheets 10
and 20 to interconnect between the electronic parts through the
dielectric material.
[0096] The connection of one printing board to another printing
board through the dielectric sheet 10, for example, provides the
other printing board with solid capacitor through the first
penetrating region 2a. The dielectric sheet 10 thus serves to
complement the circuit of electronic parts to be connected.
[0097] As is well known, the capacitance C [F] of the solid
capacitor is determined by permittivity .epsilon. (epsilon) [F/m],
distance d [m] of insulator (dielectric material), and area A
[m.sup.2] of the insulator (dielectric material). The capacitance C
may be obtained by the equation:
C=.epsilon.(epsilon).times.(A/d).
[0098] Assuming that the first penetrating region 2a of the
dielectric sheet 10 is a solid capacitor, the thickness t of the
dielectric sheet 10 is equivalent to the distance d of the
insulator (dielectric material) and the area of the first
penetrating region 2a is equivalent to the area A of the insulator
(dielectric material). The characteristic value of permittivity
.epsilon. (epsilon) is determined by a mixing ratio of barium
titanate into the silicone rubber in the ferroelectrics member
forming the first penetrating region 2.
[0099] A plate thickness, area or a mixing ratio of barium titanate
into the silicone rubber is therefore accordingly determined to
form a solid capacitor having desired capacitance in the dielectric
sheet 10.
[0100] FIG. 2A is an outline view of a dielectric sheet 30 showing
a modified example of the second penetrating region 3a having
conductivity further formed on the dielectric sheet 10 shown in
FIG. 1A. The dielectric sheet 30 according to the present invention
is a rectangular-shaped sheet comprising a rectangular first
penetrating region 22a having high permittivity in the
non-conductive sheet-shaped elastomer 16, and it further comprises
a second penetrating region 3a having conductivity formed in
rectangular shape. The sheet-shaped elastomer 16 is composed of
silicone rubber, for example.
[0101] FIG. 2B is a modified example of dielectric sheet 20 shown
in FIG. 1B, wherein a sheet-shaped elastomer 17 comprises a first
penetrating region 22b having high permittivity formed in a
circular shape. Similarly, a sheet-shaped elastomer 17 comprises a
second penetrating region 3b having conductivity formed in a
circular shape.
[0102] In the embodiment in FIGS. 2A and 2B, circular and
rectangular shaped second penetrating regions having conductivity
are illustrated, however, the second penetrating region may be of
any other shape as desired. It may be, for example, polygonal or
elliptical shape, or any other closed and curved surface.
[0103] Also, in the dielectric sheet 30 and 40, the first
penetrating regions 22a and 22b having high permittivity, and the
second penetrating regions 3a and 3b having conductivity are formed
in an identical shape respectively, however, the first penetrating
regions and the second penetrating regions may be formed in
different shapes respectively.
[0104] In the dielectric sheet 30, for example, the rectangular
shaped first penetrating region and circular shaped second
penetrating region may be arranged, or in the dielectric sheet 40,
circular shaped first penetrating region and rectangular shaped
second penetrating region may be arranged.
[0105] It can be considered that the second penetrating regions 3a
and 3b having conductivity are formed of conductive elastomer,
which is obtained by mixing non-conductive material such as a
silicone rubber with conductive material in order to keep the
volume specific resistance low (not exceeding 1 .OMEGA.cm, for
example).
[0106] As one example of a manufacturing method of the
afore-mentioned dielectric sheets 30 and 40, a mold cavity
corresponding to a shape of the second penetrating regions 3a or 3b
is stamped through a sheet-shaped elastomer 16 or 17, a member
formed as a conductivity member is then inserted into the obtained
cavity to form the second penetrating region 3a or 3b. The second
penetrating regions 3a or 3b inserted respectively as a molding
member is bonded with sheet-shaped elastomer 16 or 17 respectively
by a coupling agent. The sheet-shaped elastomer 16, the first
penetrating region 22a, and the second penetrating region 3a have
an identical thickness, and the sheet-shaped elastomer 17 and the
second penetrating region 3b has an identical thickness.
[0107] Non-conductive elastomer and coupling agent used in the
dielectric sheets 10 and 20 are also used here.
[0108] The dielectric sheets 30 or 40 shown in FIG. 2A or 2B is
identical with the dielectric sheet 10 or 20 shown in FIGS. 1A and
1B except that further comprises second penetrating regions 3a or
3b having conductivity.
[0109] The second penetrating region 3a or 3b of the dielectric
sheets 30 or 40 according to the present invention may be used as a
conductive material of the elastomer connector, however, the
resistance value of the conductive material provided in known
elastomer connectors of anisotropic conductive sheet type is
determined to a degree that is low enough to keep the elasticity
property of the portion. On the other hand, the resistance value of
the second penetrating region 3a or 3b of the dielectric sheets 30
or 40 according to the present invention is determined to a degree
that is high enough to keep the elasticity property of the
region.
[0110] In brief, the second penetrating region 3a or 3b is formed
in a way that it can be used as a resister in the electrical
circuit. The characteristic value of resistance value of the second
penetrating region 3a or 3b is determined by a volume of the second
penetrating region 3a or 3b, types of conductivity materials mixed
in the silicone rubber composing the second penetrating region 3a
or 3b, and a mixing ratio of conductivity materials.
[0111] A plate thickness and area of the second penetrating region
3a or 3b, or type or mixing ratio of conductivity materials mixed
in the silicone rubber is therefore accordingly determined to
provide the dielectric sheet 30 or 40 with a solid resistance of
desired resistance value.
[0112] The dielectric sheet 30 can be provided with a so-called
smoothing circuit by using the first penetrating region 2a as a
solid capacitor, adjusting the resistant value of the second
penetrating region 3a, and providing a desired solid resistance
with the dielectric sheet 30.
[0113] For example, when one printing board is connected to other
printing board through the dielectric sheet 30 and accordingly
wired to one of the printing board, it provides the other printing
board with the smoothing circuit. The dielectric sheet 30 thus
serves to complement the smoothing circuit to the circuit of
electronic parts to be connected.
[0114] The following description refers a dielectric sheet that
comprises the first penetrating region having high permittivity and
the second penetrating region having conductivity as a "smoothing
circuit sheet", which is distinguished from a "dielectric sheet"
that only comprises the first penetrating region having high
permittivity. These two terms will be completely distinguished in
the following description unless otherwise required.
[0115] The dielectric sheet or smoothing circuit sheet according to
the present invention thus serves to complement the circuit of
electronic parts to be connected. It can be considered that a
plurality of first penetrating regions having high permittivity or
a plurality of second penetrating regions having conductivity may
be formed in the dielectric sheet or smoothing circuit sheet.
[0116] FIGS. 3A and 3b shows a dielectric sheet having a plurality
of first penetrating regions having high permittivity and a method
for manufacturing the same. In FIGS. 3A and 3b, an arrow L
represents a line direction (transverse thickness direction) and an
arrow R represents a row direction (longitudinal thickness
direction)
[0117] As shown in FIG. 3A, a plurality of rectangular-shaped
penetrating holes 11a are formed in longitudinal and crosswise
directions (in line and row directions) in a non-conductive cubic
block 110 molded of non-conductive elastomer. Similarly, as shown
in FIG. 3B, a plurality of circular-shaped penetrating holes 11b
are formed in longitudinal and crosswise directions (in line and
row directions) in a non-conductive cubic block 111 molded of
non-conductive elastomer.
[0118] Vulcanized ferroelectric elastomer having a shape
corresponding to the rectangular-shaped penetrating holes 11a or
circular-shaped penetrating holes 11b are inserted to the
rectangular-shaped penetrating holes 11a or circular-shaped
penetrating holes 11b, respectively.
[0119] The non-conductive block 110 and 111 are not vulcanized.
However, the vulcanized ferroelectric elastomer and non-vulcanized
non-conductive block can be bonded together by inserting the
vulcanized ferroelectric elastomer into the penetrating holes 11a
or 11b, and then heating the non-vulcanized non-conductive block
110 and 111.
[0120] For this reason, the coupling agent is not necessarily
provided in the above manufacturing method, but may be optionally
provided or may even be deleted from the process.
[0121] Non-conductive block 110 is cut-off to a predetermined
thickness t through a line X-X to obtain a rectangular shaped
dielectric sheet 10a having a thickness t. In the dielectric sheet
10a, a plurality of rectangular shaped first penetrating regions
222a are formed in longitudinal and crosswise directions.
Similarly, non-conductive block 111 is cut-off in a predetermined
thickness t through a line X-X to obtain a rectangular shaped
dielectric sheet 10b having a thickness t. In the dielectric sheet
10b, a plurality of circular shaped first penetrating regions 222b
is formed in longitudinal and crosswise directions.
[0122] Non-conductive block 110 and 111 may be cut by using blades
such as super-steel cutters and ceramic cutters, by grinders such
as fine cutters, by saws, or by other machining devices or cutting
apparatus (including non-contact type cutting apparatus such as
laser cutters).
[0123] In addition, in a process of cutting, machining fluid such
as machining oil can be used or dry-cutting methods may be adopted
in order to prevent overheating, to obtain smooth cutting surface,
or to satisfy any other purposes.
[0124] In this way, the conventionally difficult creation of
dielectric sheet of which thin sheet-shaped elastomer is the main
body and the creation of dielectric sheet of which thick
sheet-shaped elastomer is the main body can be facilitated. The
thickness of dielectric sheets are generally approximately 1 mm, or
can be approximately 100 nm or less when thin sheet is required, or
can even be approximately 50 nm or less when thinner sheet is
particularly desired, or can reversely be made to several mm. In
the present embodiment, the thickness is approximately 1 mm.
[0125] The pitch PL in a line direction L and the pitch PR in a row
direction R of the first penetrating region 222a and 222b having
high permittivity can be determined arbitrarily. The first
penetrating region can be arranged in regular intervals of 1/10
inches or 2.54 mm when pitches PL and PR are adjusted in the land
pattern arrangement of the printing board. The pitch PL and PR is
preferably 70 micrometers or less when adjusted to the fine pitch
of IC.
[0126] FIGS. 4A and 4b shows a manufacturing method of smoothing
circuit sheet that is a type of dielectric sheet comprising a
plurality of first penetrating regions having high permittivity and
second penetrating regions having conductivity respectively.
[0127] As shown in FIG. 4A, a plurality of rectangular-shaped
penetrating holes 11a are formed in longitudinal and crosswise
directions in a non-conductive cubic block 110 molded of
non-conductive elastomer. Similarly, as shown in FIG. 4B, a
plurality of circular-shaped penetrating holes 11b are formed in
longitudinal and crosswise directions in a non-conductive cubic
block 111 molded of non-conductive elastomer.
[0128] Vulcanized ferroelectric elastomer having a shape
corresponding to the rectangular-shaped penetrating holes 11a and
vulcanized conductive elastomer are inserted alternatively into the
rectangular-shaped penetrating holes 11a.
[0129] Similarly, vulcanized ferroelectric elastomer having a shape
corresponding to the rectangular-shaped penetrating holes 11b and
vulcanized conductive elastomer are alternatively inserted into the
circular-shaped penetrating holes 11b.
[0130] The non-conductive block 110 having rectangular-shaped
penetrating holes 11a and the non-conductive block 111 having
circular-shaped penetrating holes 11b are heated to bond the
vulcanized ferroelectric elastomer and the vulcanized conductive
elastomer.
[0131] Non-conductive block 110 is cut-off to a thickness t through
a line X-X to obtain a smoothing circuit sheet 10c having a
thickness t. In the smoothing circuit sheet 10c, a plurality of
rectangular shaped first penetrating regions 222c having high
permittivity, and a plurality of rectangular shaped second
penetrating regions 33a having conductivity are alternatively
formed in longitudinal and crosswise directions.
[0132] Similarly, non-conductive block 111 is cut-off to a
thickness t through a line X-X to obtain a smoothing circuit sheet
10d having a thickness t. In the smoothing circuit sheet 10d, a
plurality of circular shaped first penetrating regions 222d having
high permittivity, and a plurality of circular shaped second
penetrating regions 33b having conductivity are alternatively
formed in longitudinal and crosswise directions.
[0133] The non-conductive blocks 110 and 111 may be cut off in a
similar way described in aforementioned manufacturing process of
dielectric sheet 10a and 10b.
[0134] This facilitates preparation of smoothing circuit sheet
having various thicknesses, in spite of difficulties generally
existing in preparation of thin smoothing circuit sheets. The
thickness of smoothing circuit sheet are generally approximately 1
mm, or can be approximately 100 nm or less when thin sheet is
required, (or can even be approximately 50 nm or less when thinner
sheet is particularly desired), or can reversely be made to several
mm. In the present embodiment, the thickness is approximately 1
mm.
[0135] The pitch PL in a line direction L and the pitch PR in a row
direction R of the first penetrating region 222c and 222d having
high permittivity and second penetrating region 33a and 33b having
conductivity can be determined arbitrarily. It can be considered
that each penetrating region be arranged in a regular intervals of
1/10 inches or 2.54 mm when pitches PL and PR are adjusted in the
land pattern arrangement of the printing board. The pitch PL and PR
is preferably 70 micrometers or less when adjusted to the fine
pitch of IC.
[0136] FIGS. 5 to 8 illustrate other processes for manufacturing
dielectric sheets having similar shape as dielectric sheet 10a
shown in FIG. 3A.
[0137] FIG. 5 shows a process for forming a sheet member laminating
block 70, in which a plurality of dielectric sheet members 50 that
are plate shaped elastomer having high permittivity, and a
plurality of non-conductive sheet members 60 that are plate shaped
non-conductive elastomer are prepared, and the dielectric sheet
members 50 and the non-conductive sheet members 60 are
alternatively laminated with one another.
[0138] The dielectric sheet members 50 and non-conductive sheet
members 60 are provided with a coupling agent therebetween for
coupling of each sheet members. The thickness of non-conductive
sheet member 60 is shown as W1 and the thickness of dielectric
sheet member 50 is shown as W2.
[0139] The non-conductive sheet member 60 is arranged at the very
bottom of the sheet member laminating block 70. It may be
considered that the thickness W1 of non-conductive sheet member 60
is equivalent to the distance between adjacent first penetrating
regions 222a in the dielectric sheet 10a shown in FIG. 3A. It may
also be considered that the thickness W2 of dielectric sheet member
50 laminated on the non-conductive sheet member 60 is equivalent to
the length of one side (herein referred to as a "transverse
thickness direction") of first penetrating regions 222a in the
dielectric sheet 10a shown in FIG. 3A. The thickness of dielectric
sheet member or non-conductive sheet member can be changed to
adjust the space intervals and size of the first penetrating
region, thereby achieving a fine pitch required in the highly
integrated circuit etc.
[0140] The alternative lamination of the dielectric sheet members
and non-conductive sheet members may also include alternative
lamination in which two or more dielectric sheet members are
laminated continuously and then one or more non-conductive sheet
members are laminated thereon. Or it may also include alternative
lamination in which two or more non-conductive sheet members are
laminated continuously and then one or more dielectric sheet
members are laminated thereon.
[0141] FIG. 6 a shows a process for cutting off the sheet member
laminating block 70 prepared by afore mentioned sheet member
laminating process. The sheet member laminating block 70 is cut
through a line Y-Y with a thickness W3 to obtain a striped sheet
member 71. The thickness W3 of the striped sheet member 71 is
equivalent to a length of one side perpendicular to the transverse
thickness direction (referred to as a "longitudinal thickness
direction") of the first penetrating region 222a in the dielectric
sheet 10a.
[0142] FIG. 7 shows a dielectric sheet block 72 formed by
alternatively laminating the striped sheet members 71 obtained from
the above cutting process of the sheet member laminating block and
plate-shaped non-conductive sheet members 61. The figure also shows
the dielectric sheet block 72 being cut in a predetermined
width.
[0143] The non-conductive sheet member 61 has an identical length
of transverse width and longitudinal width as the striped sheet
member 71 does, and is alternatively laminated with the striped
sheet member 71. These sheet members are provided with a coupling
agent therebetween for coupling of each sheet members.
[0144] The thickness W4 of the non-conductive sheet member 61 is
arbitrarily determined, however, may be considered as equivalent to
the adjacent distance between the first penetrating regions 222a
and the dielectric sheet 10a shown in FIG. 3A, and therefore
determining the pitch PL and PR of the first penetrating regions
222a according to the thickness W3 and W4 of the non-conductive
sheet member 60 and 61.
[0145] The resultant dielectric sheet block 72 is cut-off with a
thickness t through a line Z-Z to obtain a dielectric sheet
10e.
[0146] FIG. 8A is a plan view of a dielectric sheet obtained from
the process shown in above, and FIG. 8B is a transverse
cross-sectional view of the dielectric sheet shown in FIG. 8A. As
shown in FIG. 8A, a plurality of first penetrating regions 222a
having high permittivity is in a rectangular shape and has a
transverse thickness in a length of W2 and a longitudinal thickness
in a length of W3, and arranged in longitudinal and crosswise
directions of the dielectric sheet 10e with regularities.
[0147] As shown in FIG. 8A, a plurality of first penetrating
regions 222a may be interspersed in the dielectric sheet 10e. The
values of W1 to W4 are arbitrarily determined. The dielectric sheet
10e in FIG. 8A is in the identical shape to that of the dielectric
sheet 10a in FIG. 3A, however, the dielectric sheet 10e is formed
by laminating sheet-shaped elastomer of non-conductive material,
whereas the sheet-shaped elastomer which is non-conductive material
of the dielectric sheet 10a in FIG. 3A is integrally molded.
[0148] FIGS. 9 to 12 show processes for manufacturing a smoothing
circuit sheet in other manufacturing methods. The figures show a
smoothing circuit sheet having the identical shape to that of the
smoothing circuit sheet 10c shown in FIG. 4A, the smoothing circuit
sheet 10c comprising a plurality of first penetrating regions
having high permittivity and a plurality of second penetrating
regions having conductivity.
[0149] FIG. 9 shows how a sheet member laminating block 90 is
formed by laminating sequently a plurality of dielectric sheet
members 50, non-conductive sheet members 60, and conductive sheet
members 80 of a plate-shaped elastomer having conductivity in a
predetermined combination thereof.
[0150] In the sheet member laminating block 90, the non-conductive
sheet member 60 is arranged in the very bottom, and the dielectric
sheet member 50 is arranged thereon. Following the arrangement is
the non-conductive sheet member 60, and then conductive sheet
member 80. The sequence continues. These sheet members are provided
with a coupling agent therebetween for coupling of respective sheet
members. The thickness of non-conductive sheet member 60 is shown
as W1, the thickness of dielectric sheet member 50 is shown as W2,
and the thickness of conductive sheet member 80 is shown as W3.
[0151] In FIG. 9, the dielectric sheet member 50 and conductive
sheet member 80 are sandwiched by two non-conductive sheet members
60. The non-conductive sheet members 60 may be of two or more
layers, or the dielectric sheet member 50 and conductive sheet
member 80, respectively, are also of two or more layers.
[0152] A plurality of layers of the dielectric sheet members 50,
non-conductive sheet members 80, and conductive sheet members 80
are laminated and bonded to form the sheet member laminating block
90. A part of which, a block 90a, may be bonded to a block 90a
which has similar structure to form the sheet member laminating
block 90. Or a plurality of sheet members may sequentially be
laminated and bonded to form the sheet member laminating block
90.
[0153] In FIG. 9, it may be considered that the thickness W1 of the
non-conductive sheet member 60 is equivalent to the distance
between the adjacent first penetrating region 222c and second
penetrating region 33a. It may also be considered that the
thickness W2 of the dielectric sheet member 50 is equivalent to one
side ("transverse thickness") of the first penetrating region 222c
shown in FIG. 4A, and similarly, the thickness W3 of the conductive
sheet member 80 is equivalent to one side ("transverse thickness")
of the second penetrating region 33a.
[0154] In FIG. 10, the sheet member laminating block 90 formed by
the aforementioned sheet member laminating process is cut. The
sheet member laminating block 90 is cut with a thickness of W4
along a line Y-Y to obtain a striped sheet member 91. The thickness
W4 of the striped sheet member 91 is equivalent to the length of
one side perpendicular to the thickness ("longitudinal thickness")
of the first penetrating region 222c and second penetrating region
3a in FIG. 4A.
[0155] In FIG. 11, the striped sheet member 91 obtained from a
cutting process of aforementioned sheet member laminating block 90
and non-conductive sheet member 61 are alternatively laminated to
form a smoothing circuit sheet block 92. The figure also shows the
smoothing circuit sheet block 92 being cut in a predetermined
thickness.
[0156] The non-conductive sheet member 61, having an identical
thickness and length with the striped sheet member 91, is laminated
alternatively with the striped sheet member 91. These sheets are
provided with a coupling agent therebetween for coupling of each
sheet members.
[0157] The thickness W5 of the non-conductive sheet member 61 is
arbitrarily determined, however, may be considered as equivalent to
the adjacent distance between the first penetrating regions 222c
and second penetrating region 33a shown in FIG. 4A, and therefore
determining the pitch PL and PR of the first penetrating regions
222c having high permittivity and second penetrating region 33a
having conductivity according to the thickness W4 and W5 of the
non-conductive sheet member 60 and 61.
[0158] The resultant smoothing circuit sheet block 92 is cut-off
with a thickness t through a line Z-Z to obtain a smoothing circuit
sheet 10f.
[0159] FIG. 12A is a plan view of a smoothing circuit sheet 10f
obtained from the process shown above and FIG. 12B is a transverse
cross-sectional view of the smoothing circuit sheet shown in FIG.
12A. As shown in FIG. 12A, a plurality of first penetrating regions
222c having high permittivity is in a rectangular shape and has a
transverse thickness W2 and a longitudinal thickness W5, and
arranged in longitudinal and crosswise directions of the dielectric
sheet 10f with regularities. Similarly, a plurality of second
penetrating regions 33a having conductivity is in a rectangular
shape and have a transverse thickness W3 and a longitudinal
thickness W5, and arranged in longitudinal and crosswise directions
of the smoothing circuit sheet 10f with regularities.
[0160] As shown in FIG. 12A, a same number of the first penetrating
regions 222c having high permittivity and the second penetrating
regions 33a having conductivity, respectively, are formed in the
smoothing circuit sheet 10f are formed in pairs. In addition, the
first penetrating regions 222c having high permittivity and the
second penetrating regions 33a having conductivity may be formed in
pairs and adjacent to each other in the smoothing circuit sheet as
shown in FIG. 12A. Alternatively, the first penetrating regions
having high permittivity and the second penetrating regions having
conductivity may be interspersed with no regularity in the
smoothing circuit sheet.
[0161] The smoothing circuit sheet 10f in FIG. 12A has almost
identical structure to that of the dielectric sheet 10c in FIG. 4A,
however, the smoothing circuit sheet 10f is formed by laminating
sheet-shaped elastomer of non-conductive material, whereas the
sheet-shaped elastomer which is non-conductive material of the
dielectric sheet 10c is integrally molded.
[0162] The dielectric sheet according to the present invention can
thus have the effect of complementing circuits in the electronic
parts to be connected to the dielectric sheet, by having the
capacitor or electrical element of the resister being incorporated
as elastomer, while ensuring the electrical insulating property and
elasticity in the surface direction.
[0163] In addition, the area and pitch of the first penetrating
region having high permittivity and second penetrating region
having conductivity can be freely determined, and the fine pitches
desired in the highly integrated dielectric sheet are easily
achieved. The non-conductive member in the first penetrating region
and second penetrating region are chemically bonded (cross-linked
by rubber) and no conductive portion of wire metal is adopted, thus
there is no trouble of missing and lacking of the conductive
portion.
[0164] In the dielectric sheet according to the present invention,
as described above, the first penetrating region having high
permittivity is formed in the non-conductive sheet-shaped
elastomer, or the first penetrating region and the second
penetrating region having conductivity, respectively, is formed in
the non-conductive sheet-shaped elastomer. This can provide greater
degree of freedom of the circuit designing of the electronic parts
to be connected to the dielectric sheet. In addition, the
dielectric sheet can correspond to smaller and thinner electronic
parts to be connected to the dielectric sheet. One or plurality of
penetrating region(s) may be provided with the dielectric
sheet.
* * * * *